Homebrew System: Is there a point to dragons that breathe something other than fire?

[Scalenex]

So I've created a system adapting a White Wolf like d10 based system to a high fantasy setting like most Pathfinder games.

I have spells and magic effects that resist energy attacks. That's it. Unlike D&D 5th edition where damage type matters a lot. Cold, electricity, fire, sonic, divine rays, infernal rays, and the like all do the same basic damage, they just look different cosmetically.

Is there a story purpose to have some dragons breathe fore and some dragons breathe other forms of energy, or should I just stick with the classic and have them all breathe fire.

I don't have several subspecies of dragons. But dragons are so magical, they vary a lot. A dragon is likely to have about a quarter a third of his cosmetic and magical traits from the mother, a third from his father, and a third from his early formative experiences.

I used a point based skill system for player characters and I use a similar system for dragons. That have certain points totals based on their age, and a dragon can decide who smart, strong, fast, tough, charming it is based on these finite points. Magic comes out of this too. Also, they can allocate extra points to their breath weapon to make it stronger.

Dragons that are more subtle typically develop a coloration to blend in with their favored environment. Dragons that are vain tend to develop coloration that makes them stand out. Dragons that focus on their magical abilities tend to have shiny scales or exotic scale patterns. Some real world scholars say dragons combine the three predators that scared early humans: snakes, raptor birds, and big cats.

At least in my world, physically oriented dragons develop more catlike bodies and socially oriented dragons tend to develop more snakelike bodies.

[Silly Name]

There's no universal answer to this, because what effect a dragon's breath has is entirely dependent on the story and setting you want to tell. However, I will note that mythological dragons didn't necessarily breathe (just) fire: some dragons breathed poison, some breathed both poison and fire, some didn't have any peculiar breath at all...

It's really up to you how varied you want your dragons to be. If you want some dragons to breathe fire, other to spew poison, some to breathe ice and snow, and a few to have no magical breath but instead possess some other power, such as a petrifying gaze, that's absolutely valid and needs no more explanation than "I like it that way" - and the same goes for deciding that dragons in your world all breathe fire and only fire.

In short, if mechanics-wise damage is damage and it doesn't matter if it's coming from being blasted with fire or zapped with lightning, dragons breathing anything other than fire is purely a flavour decision.

[Chronos]

I think it's rather core to the dragon identity that they're the top of the food chain, every food chain. If your setting has arctic environments with things like frost giants and winter wolves that deal cold damage, the biggest baddest big bad in that environment will be a cold-breathing dragon. If you want a Lord of Storms monster, it'd be a lightning-breathing dragon. Monsters that embody rot and decay? The worst of them will be an acid-breathing dragon, and so on.